Q. Jesus said, referring to himself, “The Son of Man must suffer many things and be rejected by the elders, the chief priests and the teachers of the law, and he must be killed and on the third day be raised to life.” But Jesus died on a Friday and rose on a Sunday. How was that the “third day”?
The answer has to do with how people in the biblical culture reckoned time. Today was considered the first day, tomorrow the second day, and the day after tomorrow the third day. The day before yesterday was considered the third day going in the other direction. There is a Hebrew idiom that means “it was not like that in the past” that says literally, “It was not like that yesterday, three days,” meaning, “It was not like that yesterday or the day before yesterday.”
We get one clear indication of this usage in the reply Jesus gave when he was told that Herod wanted to kill him. He said, “I will keep on driving out demons and healing people today and tomorrow, and on the third day I will reach my goal. In any case, I must press on today and tomorrow and the next day.” This shows clearly that the “third day” is the day after tomorrow.
So the way people reckoned time, Friday would have been the first day, Saturday the second day, and Sunday the third day.